+/**
+ * Store the stripe size of \a layout in \a size.
+ *
+ * \retval 0 Success.
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_stripe_size_get(const struct llapi_layout *layout,
+ uint64_t *size);
+
+/**
+ * Set the stripe size of \a layout to \a stripe_size.
+ *
+ * \retval 0 Success.
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_stripe_size_set(struct llapi_layout *layout, uint64_t size);
+
+/******************** Stripe Pattern ********************/
+
+/**
+ * Store the stripe pattern of \a layout in \a pattern.
+ *
+ * \retval 0 Success.
+ * \retval -1 Error with status code in errno.
+ */
+int llapi_layout_pattern_get(const struct llapi_layout *layout,
+ uint64_t *pattern);
+
+/**
+ * Set the stripe pattern of \a layout to \a pattern.
+ *
+ * \retval 0 Success.
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_pattern_set(struct llapi_layout *layout, uint64_t pattern);
+
+/******************** OST Index ********************/
+
+/**
+ * Store the index of the OST where stripe number \a stripe_number is stored
+ * in \a index.
+ *
+ * An error return value will result from a NULL layout, if \a
+ * stripe_number is out of range, or if \a layout was not initialized
+ * with llapi_layout_lookup_by{path,fd,fid}().
+ *
+ * \retval 0 Success
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_ost_index_get(const struct llapi_layout *layout,
+ uint64_t stripe_number, uint64_t *index);
+
+/**
+ * Set the OST index associated with stripe number \a stripe_number to
+ * \a ost_index.
+ * NB: This is currently supported only for \a stripe_number = 0 and
+ * other usage will return ENOTSUPP in errno. A NULL \a layout or
+ * out-of-range \a stripe_number will return EINVAL in errno.
+ *
+ * \retval 0 Success.
+ * \retval -1 Error with errno set to non-zero value.
+ */
+int llapi_layout_ost_index_set(struct llapi_layout *layout, int stripe_number,
+ uint64_t index);
+
+/******************** Pool Name ********************/
+
+/**
+ * Store up to \a pool_name_len characters of the name of the pool of
+ * OSTs associated with \a layout into the buffer pointed to by
+ * \a pool_name.
+ *
+ * The correct calling form is:
+ *
+ * llapi_layout_pool_name_get(layout, pool_name, sizeof(pool_name));
+ *
+ * A pool defines a set of OSTs from which file objects may be
+ * allocated for a file using \a layout.
+ *
+ * On success, the number of bytes stored is returned, excluding the
+ * terminating '\0' character (zero indicates that \a layout does not
+ * have an associated OST pool). On error, -1 is returned and errno is
+ * set appropriately. Possible sources of error include a NULL pointer
+ * argument or insufficient space in \a dest to store the pool name,
+ * in which cases errno will be set to EINVAL.
+ *
+ * \retval 0+ The number of bytes stored in \a dest.
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_pool_name_get(const struct llapi_layout *layout,
+ char *pool_name, size_t pool_name_len);
+
+/**
+ * Set the name of the pool of OSTs from which file objects will be
+ * allocated to \a pool_name.
+ *
+ * If the pool name uses "fsname.pool" notation to qualify the pool name
+ * with a filesystem name, the "fsname." portion will be silently
+ * discarded before storing the value. No validation that \a pool_name
+ * is an existing non-empty pool in filesystem \a fsname will be
+ * performed. Such validation can be performed by the application if
+ * desired using the llapi_search_ost() function. The maximum length of
+ * the stored value is defined by the constant LOV_MAXPOOLNAME.
+ *
+ * \retval 0 Success.
+ * \retval -1 Invalid argument, errno set to EINVAL.
+ */
+int llapi_layout_pool_name_set(struct llapi_layout *layout,
+ const char *pool_name);
+
+/******************** File Creation ********************/
+
+/**
+ * Open an existing file at \a path, or create it with the specified
+ * \a layout and \a mode.
+ *
+ * One access mode and zero or more file creation flags and file status
+ * flags May be bitwise-or'd in \a open_flags (see open(2)). Return an
+ * open file descriptor for the file. If \a layout is non-NULL and
+ * \a path is not on a Lustre filesystem this function will fail and set
+ * errno to ENOTTY.
+ *
+ * An already existing file may be opened with this function, but
+ * \a layout and \a mode will not be applied to it. Callers requiring a
+ * guarantee that the opened file is created with the specified
+ * \a layout and \a mode should use llapi_layout_file_create().
+ *
+ * A NULL \a layout may be specified, in which case the standard Lustre
+ * behavior for assigning layouts to newly-created files will apply.
+ *
+ * \retval 0+ An open file descriptor.
+ * \retval -1 Error with status code in errno.
+ */
+int llapi_layout_file_open(const char *path, int open_flags, mode_t mode,
+ const struct llapi_layout *layout);
+
+/**
+ * Create a new file at \a path with the specified \a layout and \a mode.
+ *
+ * One access mode and zero or more file creation flags and file status
+ * flags May be bitwise-or'd in \a open_flags (see open(2)). Return an
+ * open file descriptor for the file. If \a layout is non-NULL and
+ * \a path is not on a Lustre filesystem this function will fail and set
+ * errno to ENOTTY.
+ *
+ * The function call
+ *
+ * llapi_layout_file_create(path, open_flags, mode, layout)
+ *
+ * shall be equivalent to:
+ *
+ * llapi_layout_file_open(path, open_flags|O_CREAT|O_EXCL, mode, layout)
+ *
+ * It is an error if \a path specifies an existing file.
+ *
+ * A NULL \a layout may be specified, in which the standard Lustre
+ * behavior for assigning layouts to newly-created files will apply.
+ *
+ * \retval 0+ An open file descriptor.
+ * \retval -1 Error with status code in errno.
+ */
+int llapi_layout_file_create(const char *path, int open_flags, int mode,
+ const struct llapi_layout *layout);
+
+/**
+ * Set flags to the header of component layout.
+ */
+int llapi_layout_flags_set(struct llapi_layout *layout, uint32_t flags);
+int llapi_layout_flags_get(struct llapi_layout *layout, uint32_t *flags);
+const char *llapi_layout_flags_string(uint32_t flags);
+const __u16 llapi_layout_string_flags(char *string);
+
+/**
+ * llapi_layout_mirror_count_get() - Get mirror count from the header of
+ * a layout.
+ * @layout: Layout to get mirror count from.
+ * @count: Returned mirror count value.
+ *
+ * This function gets mirror count from the header of a layout.
+ *
+ * Return: 0 on success or -1 on failure.
+ */
+int llapi_layout_mirror_count_get(struct llapi_layout *layout,
+ uint16_t *count);
+
+/**
+ * llapi_layout_mirror_count_set() - Set mirror count to the header of a layout.
+ * @layout: Layout to set mirror count in.
+ * @count: Mirror count value to be set.
+ *
+ * This function sets mirror count to the header of a layout.
+ *
+ * Return: 0 on success or -1 on failure.
+ */
+int llapi_layout_mirror_count_set(struct llapi_layout *layout,
+ uint16_t count);
+
+/**
+ * Fetch the start and end offset of the current layout component.
+ */
+int llapi_layout_comp_extent_get(const struct llapi_layout *layout,
+ uint64_t *start, uint64_t *end);
+/**
+ * Set the extent of current layout component.
+ */
+int llapi_layout_comp_extent_set(struct llapi_layout *layout,
+ uint64_t start, uint64_t end);
+
+/* PFL component flags table */
+static const struct comp_flag_name {
+ enum lov_comp_md_entry_flags cfn_flag;
+ const char *cfn_name;
+} comp_flags_table[] = {
+ { LCME_FL_INIT, "init" },
+ { LCME_FL_STALE, "stale" },
+ { LCME_FL_PREF_RW, "prefer" },
+ { LCME_FL_OFFLINE, "offline" },
+ { LCME_FL_NOSYNC, "nosync" },
+};
+
+/**
+ * Gets the attribute flags of the current component.
+ */
+int llapi_layout_comp_flags_get(const struct llapi_layout *layout,
+ uint32_t *flags);
+/**
+ * Sets the specified flags of the current component leaving other flags as-is.
+ */
+int llapi_layout_comp_flags_set(struct llapi_layout *layout, uint32_t flags);
+/**
+ * Clears the flags specified in the flags leaving other flags as-is.
+ */
+int llapi_layout_comp_flags_clear(struct llapi_layout *layout, uint32_t flags);
+/**
+ * Fetches the file-unique component ID of the current layout component.
+ */
+int llapi_layout_comp_id_get(const struct llapi_layout *layout, uint32_t *id);
+/**
+ * Fetches the mirror ID of the current layout component.
+ */
+int llapi_layout_mirror_id_get(const struct llapi_layout *layout, uint32_t *id);
+/**
+ * Adds one component to the existing composite or plain layout.
+ */
+int llapi_layout_comp_add(struct llapi_layout *layout);
+/**
+ * Adds a first component of a mirror to the existing composite layout.
+ */
+int llapi_layout_add_first_comp(struct llapi_layout *layout);
+/**
+ * Deletes the current layout component from the composite layout.
+ */
+int llapi_layout_comp_del(struct llapi_layout *layout);
+
+enum llapi_layout_comp_use {
+ LLAPI_LAYOUT_COMP_USE_FIRST = 1,
+ LLAPI_LAYOUT_COMP_USE_LAST = 2,
+ LLAPI_LAYOUT_COMP_USE_NEXT = 3,
+ LLAPI_LAYOUT_COMP_USE_PREV = 4,
+};
+
+/**
+ * Set the currently active component to the specified component ID.
+ */
+int llapi_layout_comp_use_id(struct llapi_layout *layout, uint32_t id);
+/**
+ * Select the currently active component at the specified position.
+ */
+int llapi_layout_comp_use(struct llapi_layout *layout, uint32_t pos);
+/**
+ * Add layout components to an existing file.
+ */
+int llapi_layout_file_comp_add(const char *path,
+ const struct llapi_layout *layout);
+/**
+ * Delete component(s) by the specified component id or flags.
+ */
+int llapi_layout_file_comp_del(const char *path, uint32_t id, uint32_t flags);
+/**
+ * Change flags or other parameters of the component(s) by component ID of an
+ * existing file. The component to be modified is specified by the
+ * comp->lcme_id value, which must be an unique component ID. The new
+ * attributes are passed in by @comp and @valid is used to specify which
+ * attributes in the component are going to be changed.
+ */
+int llapi_layout_file_comp_set(const char *path, uint32_t *ids, uint32_t *flags,
+ size_t count);
+/**
+ * Check if the file layout is composite.
+ */
+bool llapi_layout_is_composite(struct llapi_layout *layout);
+
+enum {
+ LLAPI_LAYOUT_ITER_CONT = 0,
+ LLAPI_LAYOUT_ITER_STOP = 1,
+};
+
+/**
+ * Iteration callback function.
+ *
+ * \retval LLAPI_LAYOUT_ITER_CONT Iteration proceeds
+ * \retval LLAPI_LAYOUT_ITER_STOP Stop iteration
+ * \retval < 0 error code
+ */
+typedef int (*llapi_layout_iter_cb)(struct llapi_layout *layout, void *cbdata);
+
+/**
+ * Iterate all components in the corresponding layout
+ */
+int llapi_layout_comp_iterate(struct llapi_layout *layout,
+ llapi_layout_iter_cb cb, void *cbdata);
+
+/**
+ * FLR: mirror operation APIs
+ */
+int llapi_mirror_set(int fd, unsigned int id);
+int llapi_mirror_clear(int fd);
+ssize_t llapi_mirror_read(int fd, unsigned int id,
+ void *buf, size_t count, off_t pos);
+ssize_t llapi_mirror_copy_many(int fd, __u16 src, __u16 *dst, size_t count);
+int llapi_mirror_copy(int fd, unsigned int src, unsigned int dst,
+ off_t pos, size_t count);
+
+int llapi_heat_get(int fd, struct lu_heat *heat);
+int llapi_heat_set(int fd, __u64 flags);
+
+/** @} llapi */
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif